Princess Kate can't contain her giggles as she grabs Prince William mid-conversation

The Princess of Wales couldn't contain her giggles during a reception with her husband, Prince William, to celebrate the late Queen on Tuesday. 

Kate, 44, wearing a pink A-line dress from Emilia Wickstead, was seen grabbing onto William's arm in an affectionate moment in the historic Marble Hall at Buckingham Palace. 

William appeared to be enjoying a special Queen Elizabeth II "tribute" cocktail made from her Dubonnet – though the traditional gin was replaced by lemon juice, rosemary, and tonic due to it being a daytime event. 

The royal couple, who will one day be King and Queen themselves, appeared in bright spirits to celebrate the life and legacy of William's grandmother, with whom they both shared a special bond. 

The sweet moment of rare PDA between the two of them appeared to be the result of William cracking a joke, with Kate laughing in delight at her husband's humour. 

A full working royal turnout!

The couple was accompanied by the King and Queen, alongside a full turnout of working royals including the Duke and Duchess of Edinburgh, the Princess Royal, the Duke and Duchess of Gloucester, and the Duke of Kent and Princess Alexandra – the last two aged 90 and 89. 

The reception was designed to celebrate the life and legacy of the late Queen on the anniversary of her birth, including guests from 45 of the patronages, as well as centenarians celebrating their own 100th birthdays. 

© POOL/AFP via Getty Images

The King helped cut a cake, which was distributed to 190 guests, and personally gave out signed cards for their birthdays. They then sang a rendition of "Happy birthday", after Charles and Camilla led the royal party in from the gardens. 

Inside, the Marble Hall was decorated to look like a street party for the occasion, featuring bunting and paintings. Among the guests was Joan Hollingworth, who was wished a happy birthday by all the senior royals. 

Joking about her youthful looks, William said: "I can't believe you are 100! Do we need to call security, have you snuck in?" Afterwards, Joan said: "I said to Camilla 'I'm deaf' and she joked 'join the club'.

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"The Prince of Wales said I looked well for my age and asked what was my secret." She said  eating clotted cream fudge and eating Liquorice Allsorts are the secrets behind her old age. 

Which royals didn't attend?

Despite the big turnout, there were still some notable royal absences on Tuesday. For example, William and Kate's children, Prince George, 12, Princess Charlotte, 10, and Prince Louis, seven, did not attend. 

© Royal Family

Also not present were the Queen's middle son, Andrew Mountbatten-Windsor, and his ex-wife, Sarah Ferguson, who have withdrawn from public appearances in disgrace over their links to the convicted sex offender Jeffrey Epstein. Their daughters, Princesses Beatrice and Eugenie, didn't attend the events. 

Duchess Sophie and Prince Edward's children, Lady Louise Windsor, 22, and James, Earl of Wessex, 18, were absent. Both are likely busy with their respective studies for university and school. 

Unsurprisingly, Prince Harry and Meghan Markle have remained at home in the US following their tour in Australia last week. They haven't attended big events since stepping down as working royals in 2020. 

Meanwhile, Princess Anne's son, Peter Phillips, and Zara and Mike Tindall weren't seen; however, they are not working royals.